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                            <div style="color:gray; word-break: break-all; font-size:12px;">原英文版地址: <a href="https://www.elastic.co/guide/en/elasticsearch/reference/7.7/sql-concepts.html" rel="nofollow" target="_blank">https://www.elastic.co/guide/en/elasticsearch/reference/7.7/sql-concepts.html</a>, 原文档版权归 www.elastic.co 所有<br/>本地英文版地址: <a href="../en/sql-concepts.html" rel="nofollow" target="_blank">../en/sql-concepts.html</a></div>
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<strong>重要</strong>: 此版本不会发布额外的bug修复或文档更新。最新信息请参考 <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/index.html" rel="nofollow">当前版本文档</a>。
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<a id="sql-concepts"></a>Conventions and Terminology<a class="edit_me edit_me_private" rel="nofollow" title="Editing on GitHub is available to Elastic" href="https://github.com/elastic/elasticsearch/edit/7.7/docs/reference/sql/concepts.asciidoc">edit</a><a class="xpack_tag" href="https://www.elastic.co/subscriptions"></a>
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<p>For clarity, it is important to establish the meaning behind certain words as, the same wording might convey different meanings to different readers depending on one’s familiarity with SQL versus Elasticsearch.</p>
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<p>This documentation while trying to be complete, does assume the reader has <em>basic</em> understanding of Elasticsearch and/or SQL. If that is not the case, please continue reading the documentation however take notes and pursue the topics that are unclear either through the main Elasticsearch documentation or through the plethora of SQL material available in the open (there are simply too many excellent resources here to enumerate).</p>
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<p>As a general rule, Elasticsearch SQL as the name indicates provides a SQL interface to Elasticsearch. As such, it follows the SQL terminology and conventions first, whenever possible. However the backing engine itself is Elasticsearch for which Elasticsearch SQL was purposely created hence why features or concepts that are not available, or cannot be mapped correctly, in SQL appear
in Elasticsearch SQL.
Last but not least, Elasticsearch SQL tries to obey the <a href="https://en.wikipedia.org/wiki/Principle_of_least_astonishment" class="ulink" target="_top">principle of least surprise</a>, though as all things in the world, everything is relative.</p>

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